The Dalai Lama and Richard Dawkins may not have much in common – one is a world-renowned spiritual leader and the other a Tibetan monk – but both of them seem to think we can manage in a world without religion.

I was listening to him debating with Jonathan Sacks, the chief rabbi, in Manchester last night, and he closed the evening with the thought that we needed to put something in place of religion. I'll come back later to the question of whether this is possible. The first remarkable point is that we all know what they mean. What, after all, is religion made from, if not ethics and spirituality? How can you mix them and get something that isn't a religion?

Nonetheless, there is a clear sense that in much of the western world, "religion" means an unproblematically bad thing, while spirituality and ethics are unproblematically good. This is particularly a problem for Christianity, which is felt and seen from the outside to be primarily a matter of joyless prohibition. So a book crosses my desk by the "post-evangelical" Dave Tomlinson called How To Be a Bad Christian … And a Better Human Being. Tomlinson is by profession a priest in the Church of England.

Similarly, Francis Spufford's recent book, Unapologetic, is an attempt to remove the religion from Christianity, and show it from the inside, as a human thing, concerned, if you like, with spirituality and ethics, but set inside ordinary life as it is ordinarily lived.

The Dalai Lama has his own problems with "religion". It is very much the USP of Buddhism in the west that it is not a religion – that it is concerned solely with truth and makes no compromises with earthly power or ancient superstitions. But of course the religious aspects are there for anyone who looks into them: the role of Buddhism in the Sri Lankan civil war; the various and multiplying scandals around lamas who have set up in the west, and even the monks who set themselves ablaze in Tibet.

To some extent the distinction between religion and spirituality is clear. Spirituality is the voice I hear that tells me what to do and that I am valuable, whereas religion is when someone else's voices purport to tell me what to do and whether I am good. Religion seems to be about power relationships, and spirituality about authenticity. But this isn't really a distinction that bears much thought. The organisation of society and the construction of legitimacy must involve power relations and both must involve shared visions and their collective interpretation.

I think it is a consequence of the replacement of Christianity by a largely secular and individualistic ideology that justifies itself as more rational than what it replaced. In fact, of course, it is little more rational and just as much concerned with power relations as ever Christendom was. But if you want something to do the work of religion in the world today, to help us dramatise, represent and understand our own society and our place in the world, you must call it anything but "religious".

It was Dawkins who best illuminated this point towards the end of his debate with Lord Sacks. Sacks had early on got in a hard low blow when he described one of the rhetorical gargoyles that decorate The God Delusion as "profoundly antisemitic". But towards the end, Dawkins rallied, and described how he wanted a post-religion ethics worked out without reference to tradition, authority or revelation. Uninfluenced by these things, people could get together and discuss from first principles what sort of morals were needed to ensure a good society.

This idea is of course completely impossible. It has never happened in history. It could never happen and it never will. Everyone grows up inside some tradition, under some authority and given some revelation – those are three things that every parent provides for their children, and which children will always find, even if they have to create it. When a rationalist tell his daughter not to trust authority, she believes him because he's her father and she loves him.

And if we make believe a little more, and imagine that there should ever be a community of adults all in their separate ways entirely liberated from tradition, authority and revelation, how could they possibly reason together about morality? What stories would they have in common? What language would they have?

Of course Dawkins's idea is attractive; of course we know what it means so long as we don't stop to think about it. But it is not actually true. It is an imaginary story whose truth is assumed because it seems to make morality possible. In the hard and narrow sense of myth, it is a myth just like Adam and Eve. We can play with it, and make use of it. But it is quite as "religious" as the rival stories it is meant to displace. That is inevitable. Religion is not something imposed on us by priests any more than economics is imposed on us by bankers. Both grow out of the nature of human societies.